Software as a service (SaaS), also referred to as on-demand software, is an example of a software delivery model in which software is centrally hosted on the cloud. Typically, an enterprise will enter into an agreement with a software provider in which the software provider provides hardware and software maintenance and support to allow the enterprise to focus on its core business model. In return, the enterprise pays a setup fee and a periodic subscription fee. The software provider hosts an application centrally so that software updates can be made without requiring the enterprise to install new software. SaaS has been used for many business applications, including accounting, customer relationship management, human resource management and service desk management. However, security concerns may prevent an enterprise from realizing the advantages of SaaS.